,000. >> woodruff: president obama and governor mitt romney were slugging it out again today on the campaign trail, both of them in the battleground state of ohio. and both of them mindful of the need to turn out younger voters, who went overwhelmingly for mr. obama in 2008, but who are proving more elusive this year. i traveled to the columbus area this past weekend ahead of the candidates to find out just how elusive. >> fired up! ready to go! >> woodruff: ohio state university students about to head out from an obama campaign office to register voters, yell a familiar refrain. >> fired up! ready to go! >> woodruff: they are a coveted voting block for the president, in this fiercely contested swing state. four years ago, mr. obama won 18- to 29-year-olds nationwide by 66% to 32%. a margin so large, young people were credited with putting him over the top in several key states. >> are you registered to vote? >> woodruff: surveys suggest he's sure to capture the majority of the youngest voter block again. but after four years of watching the president grapple with the realities of governing, they'